1. Field of the Invention
The present invention relates to a system for precisely and readily adjusting and setting a mounting position of a composite control and audio head in a rotary head type magnetic video recording and reproducing apparatus (VTR).
2. Description of the Prior Art
Heretofore, in the VTR, approximately one field of television signal is recorded on a record track 1a or 1b, shown in FIG. 1, which is oblique to the longitudinal direction of a magnetic tape by two rotary heads A and B, and a control signal 3 is recorded in a predetermined positional relationship to the record track 1a or 1b by a control head 2 located at a position spaced by a predetermined tape length l from the mounting position of the rotary heads such that the heads A and B trace the record tracks 1a and 1b during playback.
An audio signal 5 is recorded on a record track on an edge of the tape by an audio head 4.
In such a VTR, the magnitude of the distance l is not critical when the signal is reproduced by the same VTR that used to record the signal, but when the signal is reproduced by a different VTR, precise tracking is not attained if the latter VTR has a different spacing distance. In this case, however, if the distance of spacing differs from the distance l by an integer multiple of control signal pitch m, precise tracking will be attained.
Heretofore, in positioning the mounting position of the control head 2, a reference magnetic tape recorded by a standard VTR is reproduced by a VTR under test and the mounting position of the control head which has been set near the point of the distance l is adjusted to a position at which an optimum video signal is reproduced (or optimum tracking is attained).
On the other hand, heretofore, the control head 2 and the audio head 4 are integrated in such a manner that magnetic gaps thereof align with each other so that the position of the audio head is established by the position of the control head.
In such a system where the control head and the audio head are integrated, if the mounting position of the control head is adjusted in the manner described above, it often occurs that the control head is positioned at a position spaced by an integer multiple of m from the predetermined distance l. In this case a problem of non-coincidence of the reproduced image and the reproduced sound occurs.
Particularly when the record tracks 1a and 1b are very narrow and closely arranged to increase the recording density, the magnitude of m is small and it is not possible to distinguish the distances l and l.+-.m from each other by visual inspection. Accordingly, non-coincidence of image and voice is apt to occur.